#!/usr/bin/env python3
# Copyright (c) 2008-9 Qtrac Ltd. All rights reserved.
# This program or module is free software: you can redistribute it and/or
# modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation, either version 2 of the License, or
# version 3 of the License, or (at your option) any later version. It is
# provided for educational purposes and is distributed in the hope that
# it will be useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
# the GNU General Public License for more details.


from PyQt4.QtCore import (QPointF, QSize, Qt, SIGNAL)
from PyQt4.QtGui import (QApplication, QBrush, QColor, QFontMetricsF,
        QFrame, QLabel, QLinearGradient, QPainter, QPolygon,
        QSizePolicy, QSpinBox, QWidget)


class YPipeWidget(QWidget):

    def __init__(self, leftFlow=0, rightFlow=0, maxFlow=100,
                 parent=None):
        super(YPipeWidget, self).__init__(parent)

        self.leftSpinBox = QSpinBox(self)
        self.leftSpinBox.setRange(0, maxFlow)
        self.leftSpinBox.setValue(leftFlow)
        self.leftSpinBox.setSuffix(" l/s")
        self.leftSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
        self.connect(self.leftSpinBox, SIGNAL("valueChanged(int)"),
                     self.valueChanged)

        self.rightSpinBox = QSpinBox(self)
        self.rightSpinBox.setRange(0, maxFlow)
        self.rightSpinBox.setValue(rightFlow)
        self.rightSpinBox.setSuffix(" l/s")
        self.rightSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
        self.connect(self.rightSpinBox, SIGNAL("valueChanged(int)"),
                     self.valueChanged)

        self.label = QLabel(self)
        self.label.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        self.label.setAlignment(Qt.AlignCenter)
        fm = QFontMetricsF(self.font())
        self.label.setMinimumWidth(fm.width(" 999 l/s "))

        self.setSizePolicy(QSizePolicy(QSizePolicy.Expanding,
                                       QSizePolicy.Expanding))
        self.setMinimumSize(self.minimumSizeHint())
        self.valueChanged()


    def valueChanged(self):
        a = self.leftSpinBox.value()
        b = self.rightSpinBox.value()
        self.label.setText("{0} l/s".format(a + b))
        self.emit(SIGNAL("valueChanged"), a, b)
        self.update()


    def values(self):
        return self.leftSpinBox.value(), self.rightSpinBox.value()


    def minimumSizeHint(self):
        return QSize(self.leftSpinBox.width() * 3,
                     self.leftSpinBox.height() * 5)


    def resizeEvent(self, event=None):
        fm = QFontMetricsF(self.font())
        x = (self.width() - self.label.width()) / 2
        y = self.height() - (fm.height() * 1.5)
        self.label.move(x, y)
        y = self.height() / 60.0
        x = (self.width() / 4.0) - self.leftSpinBox.width()
        self.leftSpinBox.move(x, y)
        x = self.width() - (self.width() / 4.0)
        self.rightSpinBox.move(x, y)


    def paintEvent(self, event=None):
        LogicalSize = 100.0

        def logicalFromPhysical(length, side):
            return (length / side) * LogicalSize
        
        fm = QFontMetricsF(self.font())
        ymargin = ((LogicalSize / 30.0) +
                   logicalFromPhysical(self.leftSpinBox.height(),
                                       self.height()))
        ymax = (LogicalSize -
                logicalFromPhysical(fm.height() * 2, self.height()))
        width = LogicalSize / 4.0
        cx, cy = LogicalSize / 2.0, LogicalSize / 3.0
        ax, ay = cx - (2 * width), ymargin
        bx, by = cx - width, ay
        dx, dy = cx + width, ay
        ex, ey = cx + (2 * width), ymargin
        fx, fy = cx + (width / 2), cx + (LogicalSize / 24.0)
        gx, gy = fx, ymax
        hx, hy = cx - (width / 2), ymax
        ix, iy = hx, fy

        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        side = min(self.width(), self.height())
        painter.setViewport((self.width() - side) / 2,
                            (self.height() - side) / 2, side, side)
        painter.setWindow(0, 0, LogicalSize, LogicalSize)

        painter.setPen(Qt.NoPen)

        gradient = QLinearGradient(QPointF(0, 0),
                                         QPointF(0, 100))
        gradient.setColorAt(0, Qt.white)
        a = self.leftSpinBox.value()
        gradient.setColorAt(1, (Qt.red if a != 0 else Qt.white))
        painter.setBrush(QBrush(gradient))
        painter.drawPolygon(QPolygon([ax, ay, bx, by, cx, cy, ix, iy]))

        gradient = QLinearGradient(QPointF(0, 0), QPointF(0, 100))
        gradient.setColorAt(0, Qt.white)
        b = self.rightSpinBox.value()
        gradient.setColorAt(1, (Qt.blue if b != 0
                                else Qt.white))
        painter.setBrush(QBrush(gradient))
        painter.drawPolygon(QPolygon([cx, cy, dx, dy, ex, ey, fx, fy]))

        if (a + b) == 0:
            color = QColor(Qt.white)
        else:
            ashare = (a / (a + b)) * 255.0
            bshare = 255.0 - ashare
            color = QColor(ashare, 0, bshare)
        gradient = QLinearGradient(QPointF(0, 0), QPointF(0, 100))
        gradient.setColorAt(0, Qt.white)
        gradient.setColorAt(1, color)
        painter.setBrush(QBrush(gradient))
        painter.drawPolygon(QPolygon(
                [cx, cy, fx, fy, gx, gy, hx, hy, ix, iy]))

        painter.setPen(Qt.black)
        painter.drawPolyline(QPolygon([ax, ay, ix, iy, hx, hy]))
        painter.drawPolyline(QPolygon([gx, gy, fx, fy, ex, ey]))
        painter.drawPolyline(QPolygon([bx, by, cx, cy, dx, dy]))



if __name__ == "__main__":
    import sys

    def valueChanged(a, b):
        print(a, b)

    app = QApplication(sys.argv)
    form = YPipeWidget()
    form.connect(form, SIGNAL("valueChanged"), valueChanged)
    form.setWindowTitle("YPipe")
    form.move(0, 0)
    form.show()
    form.resize(400, 400)
    app.exec_()

